For a few days this weekend had masses of activity at around 1-2pm for an hour or so. It was due to us having moved (borrowed) hive no. 1 forward a few feet and added new hive no. 1 in it's place. this pattern ceased once colony transferred to new hive and old hive removed from scene.
How long do bees spend out foraging before returning to hive as it would seem these were a batch all coming back at once and having a little difficulty finding their way - in fact many were entering the new hive.